Remove unused test requirements.

Author: domdfcoding

tests/requirements.txt

@@ -1,14 +1,11 @@
 coincidence>=0.2.0
 coverage>=5.1
 coverage-pyver-pragma>=0.2.1
-domdf-python-tools[testing]>=2.0.1
 html5lib>=1.1
 importlib-metadata>=3.6.0
-iniconfig!=1.1.0,>=1.0.1
 pytest>=6.0.0
 pytest-cov>=2.8.1
 pytest-datafiles>=2.0
 pytest-randomly>=3.7.0
-pytest-rerunfailures>=9.0
 pytest-timeout>=1.4.2
 sphinx-toolbox[testing]>=2.13.0b2